Exploration of Brazilian biodiversity and selection of a new oleaginous yeast strain cultivated in raw glycerol

Abstract

The objective of this study was to use glycerol generated from the synthesis of biodiesel to study the oleaginous potential of wild yeasts. An initial selection was performed via a rapid and qualitative technique by staining with Sudan Black B. Initially 129 yeasts were present, from which 5 were selected and cultivated in liquid medium containing pure or raw glycerol. The yeast LEB-M3, isolated from the Pantanal, presented lipid content of 20.46% and 56.58% for cultivation in pure and raw glycerol, respectively. This strain was genotypically identified as Candida sp. The fatty acid profile showed predominance of oleic acid (C18:1), 57.35% for cultivation in pure glycerol, and in raw glycerol linoleic acid (C18:2) was predominant (46.0%). It was possible to select a yeast with high lipid concentrations 9.14 g/L and fatty acid profile similar to vegetable oils commonly used in the synthesis of biodiesel.

Enzymatic biodiesel synthesis from yeast oil using immobilized recombinant Rhizopus oryzae lipase

“…LEB-M3, isolated from Pantanal, Brazil (Maugeri and Hernalsteens, 2007), was selected as an oleaginous yeast in previous study (Duarte et al, 2013). It was maintained in stock cultures at the Laboratory of Bioprocess Engineering (UNICAMP), on GYMP agar slants at 5°C containing (g/L): 20 glucose, 5 yeast extract, 10 malt extract, 2 KH 2 PO 4 and 20 agar, pH 5.5.…”

“…This new source has several advantages compared to other vegetable oils and animal fats: short life cycle, not depends of arable land, not competes with food sector, can be obtained independent of climatic factors and it is easier to scale-up (Li et al, 2008). Taking into account that the major economic factor to consider is the feedstock that increases the final cost to biodiesel production around 75 -80%, if we compare microbial oils with vegetables oils, the use of cheap carbon sources as residual carbon sources, diminish significantly the cost of yeast oil production (Li et al, 2008;Demirbas, 2009 LEB-M3 contain high amounts of lipids (about 50% w/w) when it is grown on crude glycerol obtained as byproduct from biodiesel synthesis (Duarte et al, 2013). The biodiesel production with this raw material challenges researchers to develop more efficient and environmental friendly processes.…”

Lipid production by yeasts growing on biodiesel-derived crude glycerol: strain selection and impact of substrate concentration on the fermentation efficiency

“…; Duarte et al . ,b; Kitcha and Cheirslip ; Louhasakul and Cheirsilp ; Wensel et al . ), or as a substrate for the production of metabolic compounds (such as citric acid, acetic acid, polyols, etc.)…”

Oleaginous Yeasts form Uruguay and Antarctica as Renewable Raw Material for Biodiesel Production

“…Moreover, the use of vegetable oils as raw material for biodiesel production competes with edible oils, thus leading to a soaring of food price. According to Duarte [24] about 600 kg of oil can be produced annually from 1 hectare of soybean, which can be used for biodiesel production. Since a lipid production of 5 gl -1 was obtained from R. graminis S12R growing in crude glycerol, about 120 000 liters of such culture would be required for the production an amount of oil equivalent to that obtained from 1 hectare of soybean.…”